Liquid crysal display including nanocapsule layer

ABSTRACT

Disclosed is a liquid crystal display device that may include a first substrate; a first electrode on the first substrate, the first electrode including a plurality of first inclined planes; a nanocapsule liquid crystal layer on the first electrode, the nanocapsule liquid crystal layer including a plurality of nano-sized capsules dispersed in a buffer layer, each of the plurality of nano-sized capsules including nematic liquid crystal molecules having a negative dielectric constant anisotropy; and a second electrode on the nanocapsule liquid crystal layer, the second electrode including a plurality of second inclined planes facing the plurality of first inclined planes, wherein the nanocapsule liquid crystal layer is substantially, optically isotropic in a normal state, and is optically anisotropic when a voltage is applied to the first and second electrodes.

This application is a Continuation of U.S. patent application Ser. No.15/359,839, filed on Nov. 23, 2016, now allowed, which is a Divisionalof U.S. patent application Ser. No. 14/518,327, filed on Oct. 20, 2014,now U.S. Pat. No. 9,535,279, and claims the benefit of Korean PatentApplication Nos. 10-2013-0126534, 10-2013-0151308 and 10-2013-0152890,filed on Oct. 23, 2013, Dec. 6, 2013 and Dec. 10, 2013, respectively,which are hereby incorporated by reference for all purposes as if fullyset forth herein.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a liquid crystal display device (LCD),and more particularly, to an LCD including a nanocapsule layer andmethod for manufacturing the same.

Discussion of the Prior Art

Recently, facing information society, display field of displayingelectric information signals has been rapidly advanced, and flat displaydevices having high performances of thin profile, lightweight and lowpower consumption have been developed and used. Among these flat displaydevices, liquid crystal display devices (LCDs) are widely used.

FIG. 1 is a cross-sectional view illustrating an LCD according to theprior art.

Referring to FIG. 1, the LCD includes a liquid crystal panel 10including an array substrate, a color filter substrate and a liquidcrystal layer 50 between the array substrate and the color filtersubstrate, and a backlight unit 60 below the liquid crystal panel 10. Afirst substrate 2 referred to as the array substrate includes a pixelregion P, and on an inner surface of the first substrate 2, a thin filmtransistor T is in each pixel region P and connected to a pixelelectrode P in each pixel region P.

On an inner surface of a second substrate 4 referred to as the colorfilter substrate, a black matrix 32 is formed in a lattice shapesurrounding the pixel region P to cover a non-display element such asthe thin film transistor T and expose the pixel electrode 28.

Red, green and blue color filters 34 are formed in the lattice shapecorresponding to the respective pixel regions P, and a common electrode36 is formed on the black matrix 32 and the color filters 34.

First and second polarizing plates 20 and 30 are attached onto outersurfaces of the first and second substrates 2 and 4, respectively.

First and second alignment layers 31 a and 31 b are formed between boththe pixel electrode 28 and the common electrode 36, and the liquidcrystal layer 50. The first and second alignment layers 31 a and 31 bare rubbed and align liquid crystal molecules.

A seal pattern 70 is formed between and along peripheral regions of thefirst and second substrates 2 and 4 and prevents leakage of the liquidcrystal.

The backlight unit 60 supplies light to the liquid crystal panel 10. Thebacklight unit 60 is categorized into a sidelight type and a directtype.

The sidelight type backlight unit has a light source on at least oneside of a light guide panel. The direct type backlight unit has a lightsource below the liquid crystal panel 10.

The sidelight type backlight unit has advantages of simplemanufacturing, thin profile, lightweight, and low power consumption.

FIG. 2 is a cross-sectional view illustrating the LCD including thebacklight unit according to the prior art.

Referring to FIG. 2, the backlight unit 60 includes a light guide plate23, a light emitting diode (LED) assembly 29 along a side of the lightguide plate 23, a reflector 25 below the light guide plate 23, and atleast one optical sheets 21 on the light guide plate 23.

The LED assembly 29 includes a plurality of LEDs 29 a, and a printedcircuit board (PCB) 29 b on which the LEDs 29 a are mounted.

Light emitted from the LED assembly 29 enters into the light guide plate23, then is refracted toward the liquid crystal panel 10, then isprocessed into light of high quality and uniform brightness passingthrough the optical sheet 21, and then enters into the liquid crystalpanel 10. Accordingly, the liquid crystal panel 10 displays images.

A portion of the light emitted from the backlight unit 60 is absorbedand reflected by the first polarizing plate 20 and thus is lost, whichmay be about 50% of all the light emitted from the backlight unit 60.Further, light is absorbed and reflected while passing through the firstand second substrates 2 and 4 and the liquid crystal layer (50 of FIG.1), and thus an additional portion of the light is lost. As such, theLCD has disadvantage in brightness compared with other types of flatdisplay displays.

Moreover, the LCD has slow response speed, and thus display quality isreduced due to afterimage.

Moreover, the LCD requires many production processes, and thusproduction efficiency is reduced.

The above LCD using the backlight unit 60 is referred to as atransmissive type LCD, in which the backlight unit 60 consumes abouttwo-third or more of a total power of the LCD. To solve this problem, areflective type LCD not using a backlight unit is suggested.

However, in the reflective type LCD, light leakage is easily caused byan external force, and thus display quality is reduced. Moreover, thereflective type LCD also requires many production processes, and thusproduction efficiency is reduced.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a liquid crystaldisplay device (LCD) including a nanocapsule layer and method formanufacturing the same that substantially obviates one or more of theproblems due to limitations and disadvantages of the prior art.

An advantage of the present invention is to provide an LCD including ananocapsule layer that can improve its response speed and/or productionefficiency.

Additional features and advantages of the invention will be set forth inthe description which follows, and in part will be apparent from thedescription, or may be learned by practice of the invention. These andother advantages of the invention will be realized and attained by thestructure particularly pointed out in the written description and claimshereof as well as the appended drawings.

To achieve these and other advantages and in accordance with the purposeof the present invention, as embodied and broadly described herein, aliquid crystal display device may include a first substrate; a firstelectrode on the first substrate, the first electrode including aplurality of first inclined planes; a nanocapsule liquid crystal layeron the first electrode, the nanocapsule liquid crystal layer including aplurality of nano-sized capsules dispersed in a buffer layer, each ofthe plurality of nano-sized capsules including nematic liquid crystalmolecules having a negative dielectric constant anisotropy; and a secondelectrode on the nanocapsule liquid crystal layer, the second electrodeincluding a plurality of second inclined planes facing the plurality offirst inclined planes, wherein the nanocapsule liquid crystal layer issubstantially, optically isotropic in a normal state, and is opticallyanisotropic when a voltage is applied to the first and secondelectrodes.

In another aspect, a liquid crystal display device may include a firstsubstrate; a first polarizing plate on an outer surface of the firstsubstrate; a first electrode on an inner surface of the first substrate;a nanocapsule liquid crystal layer that is on the first electrode andincludes nano-sized capsules which are each filled with nematic liquidcrystal molecules of negative dielectric constant anisotropy and aredispersed in a buffer layer; and a second electrode on the nanocapsuleliquid crystal layer; a phase retardation film that is on the secondelectrode and has a phase retardation value of λ/4; and a secondpolarizing plate on the phase retardation film, wherein the nanocapsuleliquid crystal layer has an optical anisotropy according to a voltagedifference between voltages applied to the first and second electrodes,and has an optical isotropy when no voltages are applied to the firstand second electrodes.

In another aspect, a liquid crystal display device may include a firstsubstrate; a plurality of first electrodes on an inner surface of thefirst substrate; a nanocapsule liquid crystal layer that is on theplurality of first electrodes and includes nano-sized capsules which areeach filled with nematic liquid crystal molecules of negative dielectricconstant anisotropy and are dispersed in a buffer layer; and a secondelectrode on the nanocapsule liquid crystal layer, wherein thenanocapsule liquid crystal layer has an optical anisotropy according toa voltage difference between voltages applied to the first and secondelectrodes, and has an optical isotropy when no voltages are applied tothe first and second electrodes.

In another aspect, a reflective type liquid crystal display device mayinclude a liquid crystal panel that includes a first electrode, a secondelectrode, and a nanocapsule liquid crystal layer between the first andsecond electrodes; a polarizing plate that is on a surface of the liquidcrystal layer through which an external light enters; a phaseretardation plate between the polarizing plate and the liquid crystalpanel; and a reflection plate that reflects light passing through thenanocapsule liquid crystal layer, wherein the nanocapsule liquid crystallayer has an optical anisotropy according to a voltage differencebetween voltages applied to the first and second electrodes, and has anoptical isotropy when no voltages are applied to the first and secondelectrodes.

In another aspect, a flexible type liquid crystal display device mayinclude a liquid crystal panel that includes a nanocapsule liquidcrystal layer on a substrate which a first electrode and a secondelectrode are formed on; a polarizing plate on the liquid crystal panel;and a backlight unit that is below the liquid crystal panel, andsupplies a predetermined linearly polarized light perpendicular to apolarizing axis of the polarizing plate, wherein the nanocapsule liquidcrystal layer has an optical anisotropy according to a voltagedifference between voltages applied to the first and second electrodes,and has an optical isotropy when no voltages are applied to the firstand second electrodes.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and areintended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention andtogether with the description serve to explain the principles of theinvention. In the drawings:

FIG. 1 is a cross-sectional view illustrating an LCD according to theprior art;

FIG. 2 is a cross-sectional view illustrating the LCD including thebacklight unit according to the prior art;

FIG. 3 is a schematic perspective view illustrating an LCD according tothe present invention;

FIGS. 4A and 4B are views illustrating the prior art LCD and an LCDaccording to an embodiment of the present invention, respectively, towhich an external force is applied;

FIGS. 5A and 5B are schematic views illustrating an LCD according to afirst embodiment of the present invention;

FIG. 6 is a schematic view illustrating a COT type LCD according to thefirst embodiment of the present invention;

FIG. 7 is a schematic view illustrating a COT type LCD without a secondsubstrate according to the first embodiment of the present invention;

FIGS. 8A and 8B arc schematic views illustrating an LCD according to asecond embodiment of the present invention;

FIG. 9 is a schematic view illustrating a COT type LCD according to thesecond embodiment of the present invention;

FIG. 10 is a schematic view illustrating a COT type LCD without a secondsubstrate according to the second embodiment of the present invention;

FIG. 11A is a schematic view illustrating an LCD according to a thirdembodiment of the present invention;

FIG. 11B is a schematic view illustrating multi-domains of FIG. 11A.

FIG. 12A is a schematic view illustrating an LCD according to a fourthembodiment of the present invention;

FIG. 12B is a schematic view illustrating multi-domains of FIG. 12A.

FIG. 13 is a perspective view illustrating an LCD according to a fifthembodiment of the present invention;

FIGS. 14A and 14B are schematic views illustrating an image displayprinciple of an LCD according to the fifth embodiment of the presentinvention;

FIGS. 15A and 15B are schematic views illustrating variation of light inthe states of FIGS. 14A and 14B, respectively;

FIGS. 16A and 16B are schematic views illustrating an image displayprinciple of an LCD according to the sixth embodiment of the presentinvention;

FIGS. 17A and 17B are schematic views illustrating an image displayprinciple of an LCD according to a seventh embodiment of the presentinvention;

FIGS. 17C and 17D are schematic views illustrating an LCD according toeighth and ninth embodiments of the present invention, respectively;

FIG. 18 is a schematic view illustrating an LCD according to a tenthembodiment of the present invention;

FIG. 19A is a schematic view illustrating an LCD according to aneleventh embodiment of the present invention; and

FIG. 19B is a schematic perspective view illustrating an optical fiberof an optical fiber type light guide plate of FIG. 19A.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Reference will now be made in detail to exemplary embodiments, examplesof which are illustrated in the accompanying drawings. The samereference numbers may be used throughout the drawings to refer to thesame or like parts.

FIG. 3 is a schematic perspective view illustrating an LCD according toan embodiment of the present invention.

Referring to FIG. 3, the LCD 100 includes a liquid crystal panel 110that includes a first substrate 112, a second substrate 114, and ananocapsule liquid crystal layer 200 between the first and secondsubstrates 112 and 114.

The first substrate 112 is referred to as a lower substrate or an arraysubstrate. A plurality of gate lines 116 and a plurality of data lines118 cross each other on an inner surface of the first substrate 112 todefine a plurality of pixel regions P.

A thin film transistor T is formed near the crossing portion of the gateand data lines 116 and 118, and is connected to a pixel electrode 124 inthe pixel region P.

The second substrate 114 is referred to as an upper substrate or a colorfilter substrate. A black matrix 132 is on an inner surface of thesecond substrate 114, and shields a non-display element such as the gateline 116, the data line 118, and the thin film transistor T exposing thepixel electrode 124. The black matrix 132 has a lattice shapesurrounding the pixel region P.

Red, green and blue color filters 134 fill openings of the black matrix132 corresponding to the respective pixel regions P. A common electrode136 covers the black matrix 132 and the color filters 134.

Even though not shown in the drawings, the first substrate 112 has anarea greater than that of the second substrate 114 so that a peripheralportion of the first substrate 112 is exposed outside the secondsubstrate 114. In the exposed portion of the first substrate 112, datapads 118 a connected to the respective data lines 118, and gate pads(not shown) connected to the respective gate lines 116 are formed.

When a gate line 116 is selected and supplied with a turn-on gate signali.e., high-level gate signal, the thin film transistor T connected tothe selected gate line 116 is turned on and an image data signal istransferred to the pixel electrode 124 through the data line 118.Accordingly, an electric field is induced between the pixel electrode124 and the common electrode 136 and controls liquid crystal molecules220 of the nanocapsule liquid crystal layer 200, and thus lighttransmittance is changed to display images.

A first polarizing plate 120 and a second polarizing plate 130 areattached onto outer surfaces of the liquid crystal panel 110. In otherwords, the first polarizing plate 120 is on an outer surface of thefirst substrate 112, and the second polarizing plate 130 is on an outersurface of the second substrate 114. The first polarizing plate 120 hasa first polarizing axis along a first direction while the secondpolarizing plate 130 has a second polarizing axis along a seconddirection perpendicular to the first direction.

A backlight unit 160 is located below the liquid crystal panel 110 tosupply light to the liquid crystal panel 110.

A sidelight type or direct type backlight unit may be used as thebacklight unit 160.

A cold cathode fluorescent lamp (CCFL), an external electrodefluorescent lamp (EEFL), or a light emitting diode (LED) may be used asa light source of the backlight unit 160.

The nanocapsule liquid crystal layer 200 includes a plurality ofnanocapsules 230 and a buffer layer 210. The nanocapsules 230 aredispersed in the buffer layer 210, with each including a plurality ofliquid crystal molecules 220 therein. The nanocapsule liquid crystallayer 200 changes light transmittance to display images.

The nanocapsule liquid crystal layer 200 is an optically isotropic typeliquid crystal layer in a normal state. Accordingly, when no electricfield is applied to the nanocapsule liquid crystal layer 200 between thepixel electrode 124 and the common electrode 136, the nanocapsule liquidcrystal layer 200 is optically isotropic. However, when an electricfield is applied, the nanocapsule liquid crystal layer 200 has abirefringence property in a direction perpendicular to the appliedelectric field.

Accordingly, when an electric field is applied, the nanocapsule liquidcrystal layer 200 may have an optically uniaxial property, with lighttransmittance being dependent upon viewing angles.

When an electric field is applied, the liquid crystal molecules 220 areregularly arranged at about 45 degrees with respect to the polarizingaxis of each of the first and second polarizing plates 120 and 130.

In more detail, the liquid crystal molecules 220 are capsuled by thenanocapsule 230 having a nanosize, and the liquid crystal molecules 220are irregularly arranged within the nanocapsule 230.

The nanocapsule 230 may have about 5% to about 95% of a total volume ofthe nanocapsule liquid crystal layer 200, and preferably, may have about25% to about 65% of the total volume of the nanocapsule liquid crystallayer 200. The buffer layer 210 occupies the rest of the total volume.

The buffer layer 210 may be made of a transparent or semi-transparentmaterial and have water-solubility, fat-solubility, or mixture ofwater-solubility and fat-solubility. The buffer layer 210 may be heatcured or UV cured.

The buffer layer 210 may have an additive to increase strength andreduce curing time.

The nanocapsule 230 may have a diameter of about 1 nm to about 320 nm,and preferable, about 30 nm to about 100 nm.

Because the nanocapsule 230 has a diameter less than any wavelengths ofvisible light, there occurs substantially no optical change due torefractive index, and optically isotropic property can be obtained.Further, scattering of visible light can be minimized.

Particularly, when the nanocapsule 230 is formed with a diameter ofabout 100 nm or less, high contrast ratio can be obtained.

The irregularly arranged liquid crystal molecules 220 and thenanocapsule 230 have different refractive indices, and thus a lightscattering may occur at the interface therebetween. Accordingly, whenlight passes through the interface, the light is scattered and becomesopaque in milk white.

However, when an electric field is applied to the nanocapsule liquidcrystal layer 200, the liquid crystal molecules 220 filling thenanocapsule 230 are regularly arranged.

In this state, the refractive index of the liquid crystal molecules 220is changed. In order to reduce or minimize a light scattering at theinterface between the nanocapsule 230 and the liquid crystal molecules220, the nanocapsule 230 and the regularly arranged liquid crystalmolecules 220 are formed such that they have refractive indices that aresubstantially close to each other, Therefore, the nanocapsule liquidcrystal layer 200 can be seen transparent.

In this case, it is preferred that a difference between the refractiveindex of the nanocapsule 220 and the refractive index of the liquidcrystal molecules 220 is within about ±0.1. The average refractive index(n) of the liquid crystal molecules 220 may be defined as follows:n=[(ne+2*no)/3] (where ne is a refractive index of a major axis of theliquid crystal molecules 220, and no is a refractive index of a minoraxis of the liquid crystal molecules 220).

Accordingly, the LCD 100 including the nanocapsule liquid crystal layer200 can be used as a display device, with its transmittance changingaccording to a variation of the voltage applied.

Further, when the electric field is induced between the first and secondsubstrates 112 and 114, the liquid crystal molecules 220 are dynamicallyrotated, and thus response speed can be fast.

Further, since the nanocapsule liquid crystal layer 200 does not have aninitial alignment to be optically anisotropic, alignment of liquidcrystal molecules may not be required, and thus no alignment layer maybe needed in the LCD 100, and also, processes for forming an alignmentlayer such as rubbing may not be needed.

Further, in case that the nanocapsules 230 are dispersed in the bufferlayer 210 made of, for example, liquid crystal, the nanocapsule liquidcrystal layer 200 may be formed, for example, by a printing method,coating method, or dispensing method. In case that the nanocapsules 230are dispersed in the buffer layer 210 made in a film type, thenanocapsule liquid crystal layer 200 may be formed, for example, by alamination method. Accordingly, a process of forming a gap between thefirst and second substrates filled with the liquid crystal layer (50 ofFIG. 1) in the prior art can be eliminated, and a process of forming theseal pattern (70 of FIG. 1) in the prior art can be eliminated.

Therefore, production efficiency can be improved.

Further, by eliminating the process of forming the alignment layer, incase that the LCD 100 is applied to a touch display device, curveddisplay device or flexible display device, light leakage, which occurswhen a rubbing axis is off a desired direction and thus arrangement ofliquid crystal molecules goes awry, can be prevented.

Therefore, the LCD 100 can be applied to a touch display device, curveddisplay device, and flexible display device.

FIGS. 4A and 4B are views illustrating the prior art LCD and an LCDaccording to an embodiment of the present invention, respectively, towhich an external force is applied.

Referring to FIG. 4A, when an external force such as a user's touch isapplied to the prior art LCD, arrangement of the liquid crystalmolecules of the prior art LCD is influenced by the external force. Inother words, arrangement of the liquid crystal molecules are awry due tothe external force, thus optic axis is off, and thus light leakage 70 iscaused.

However, referring to FIG. 4B, even when an external force such as auser's touch is applied to the LCD 100, the liquid crystal molecules 220are in the nanocapsule 230 which has the size less than the wavelengthof visible light, thus there is no influence of visible light, and thuslight leakage due to the external force can be reduced or prevented.

Accordingly, in case that the LCD 100 is applied to a flexible displaydevice, even when an external force is applied to the LCD 100, a lightleakage caused by such an external force can be reduced or prevented,because the nanocapsules 230 have a size less than the wavelength ofvisible light.

It is preferable that the liquid crystal molecules 220 are a negativetype liquid crystal molecules with a negative dielectric constantanisotropy, for example, a negative type TN (twisted nematic) liquidcrystal molecules.

The negative type liquid crystal molecules 220 are arranged in adirection perpendicular to an electric field induced between the pixelelectrode 124 and the common electrode 136.

In other words, the nanocapsule liquid crystal layer 200 uses thenanocapsules 230 having the negative type liquid crystal molecules 220therein, and when no electric field is applied, the nanocapsule liquidcrystal layer 200 has an optical isotropy, and when an electric field isapplied, the nanocapsule liquid crystal layer 200 has an opticalanisotropy.

Various embodiments of the LCD 100 using the nanocapsule liquid crystallayer 200 are explained as below.

First Embodiment

FIGS. 5A and 5B are schematic views illustrating an LCD according to thefirst embodiment of the present invention.

Referring to FIGS. 5A and 5B, the LCD of the first embodiment includesthe liquid crystal panel 110 and the backlight unit 160.

The liquid crystal panel 110 includes the first and second substrates112 and 114 facing each other, the nanocapsule liquid crystal layer 200,and the first and second polarizing plates 120 and 130 on the outersurfaces of the first and second substrates 112 and 114, respectively.

The liquid crystal panel 110 may be a vertical alignment (VA) modeliquid crystal panel. The thin film transistor (T of FIG. 3) and thepixel electrode 124 are formed on the inner surface of the firstsubstrate 112. The black matrix (132 of FIG. 3), the color filters 134,and the common electrode 136 arc formed on the inner surface of thesecond substrate 114. An overcoat layer may be formed covering the blackmatrix 132 and the color filters 134.

A plurality of protrusion patterns 150 are arranged in a line form beloweach of the pixel electrode 124 and the common electrode 136. Theprotrusion patterns 150 adjoin each other in a band shape extendingalong a first direction, for example, a length direction of the pixelelectrode 124 and the common electrode 136. The protrusion patterns 150extending along the first direction are repeatedly arranged along asecond direction perpendicular to the first direction such that hillsand valleys are alternated along the second direction.

The protrusion pattern 150 is made of a transparent insulating material,and has a vertex and first and second inclined planes at both sides ofthe vertex. The first and second inclined planes are at a cute anglewith respect to the plane of the first and second substrates 112 and114. The inclined plane of the protrusion pattern 150 of the pixelelectrode 124 faces and is parallel with the corresponding inclinedplane of the protrusion pattern of the common electrode 136.

Because of the protrusion patterns 150 described above, the pixelelectrode 124 and the common electrode 136 each have substantially thesame configuration of the protrusion patterns 150 therebelow.

In other words, the pixel electrode 124 is formed to have vertices andfirst and second inclined planes at both sides of each vertex, and thecommon electrode 136 is formed to have vertices and first and secondinclined planes at both sides of each vertex.

The incline plane of the pixel electrode 124 faces and is parallel withthe corresponding inclined plane of the common electrode 136 so thatintervals between the corresponding planes of the pixel electrode 124and the common electrode 136 are substantially identical overall.

Because the pixel electrode 124 and the common electrode 136 each havethe inclined planes, an electric field between the pixel electrode 124and the common electrode 136 is induced perpendicularly to the inclinedplanes of the pixel electrode 124 and the common electrode 136.

Accordingly, the liquid crystal molecules 220 are arrangedperpendicularly to the induced electric field according to a pixelvoltage i.e., a difference voltage between the voltages applied to thepixel electrode 124 and the common electrode 136. In this regard, theliquid crystal molecules 220 are arranged at a tilt angle of about 1degree to about 5 degrees with respect to the first substrate 112.

In other words, the liquid crystal molecules 220 are arrangedperpendicularly to the electric field between the pixel electrode 124and the common electrode 136, and a refractive index in a directionperpendicular to the electric field is manifested.

Accordingly, to realize a maximum brightness, the polarizing axes of thefirst and second polarizing plates 120 and 130 are attached to each makea 45 degrees angle with the liquid crystal molecule 220 perpendicular tothe electric field.

The backlight unit 160 supplies a scattering light close to a naturallight to the liquid crystal panel 110.

As illustrated in FIG. 5A, when a voltage is off, a scattering lightfrom the backlight unit 160 enters the first polarizing plate 120 and alinearly polarized light parallel with the polarizing axis (i.e., thetransmission axis) of the first polarizing plate 120 passes through andcomes out from the first polarizing plate 120.

However, in the voltage-off state, the liquid crystal molecules 220 arearranged randomly, the liquid crystal molecules 220 and the nano capsule230 have different anisotropies in refractive index from each other.Accordingly, optically isotropic property is obtained.

Accordingly, the linearly polarized light from the first polarizingplate 120 passes through the nanocapsule liquid crystal layer 200 as is,and does not pass through the second polarizing plate 130 having thepolarizing axis perpendicular to the polarizing axis of the firstpolarizing plate 120. Thus, a black is displayed.

As illustrated in FIG. 5B, when voltages are applied to the pixelelectrode 124 and the common electrode 136, the liquid crystal molecules220 are arranged perpendicularly to the electric field, at an angle ofabout 1 degree to about 5 degrees with respect to the plane of the firstsubstrate 112.

Accordingly, the nanocapsule liquid crystal layer 200 has an opticalanisotropy.

Accordingly, a scattering light from the backlight unit 160 entersthrough the first polarizing plate 120 so that a linearly polarizedlight comes out and other part is absorbed, and then a linearlypolarized light, which is parallel with the liquid crystal molecules220, out of the linearly polarized light coming out from the firstpolarizing light 120, passes through the liquid crystal layer 200.

Then, a linearly polarized light, which is parallel with the polarizingaxis of the second polarizing plate 130, out of the linearly polarizedlight passing through the liquid crystal layer 200 passes through thesecond polarizing plate 130, and thus a white is displayed.

As described above, the pixel electrode 124 and the common electrode 136are configured to have the inclined planes, and thus the negative typeliquid crystal molecules 220 are arranged at a tilt angle of about 1degree to 5 degrees with respect to the first substrate 112 by theelectric field between the pixel and common electrodes 124 and 136.Accordingly, the negative type liquid crystal molecules can be arrangedmore uniformly.

In other words, in case that the pixel electrode 124 and the commonelectrode 136 have the inclined plane, the negative type liquid crystalmolecules 220 randomly arranged collide one another without directivityin the process that the molecules 220 are arranged perpendicularly tothe electric field induced between the pixel and common electrodes 124and 136.

Because of such a collision among the liquid crystal molecules 220, theliquid crystal molecules 220 are not arranged in parallel with oneanother, and this causes a light leakage.

Further, this light leakage causes non-uniformity of brightness andimage.

However, according to the pixel and common electrodes 124 and 136 havingthe slanted plane in this embodiment, the liquid crystal molecules 220can be more easily rotated and uniformly arranged in the same directionby the electric field perpendicular to the slanted plane of the pixeland common electrodes 124 and 136.

Accordingly, the awry arrangement of the liquid crystal molecules 220due to the collision can be reduced or prevented, and thus a lightleakage by an awry arrangement can be also reduced or prevented.

This can improve the transmittance of the LCD 100.

Further, since the liquid crystal molecules 220 are arranged in parallelat a tilt angle of 1 degree to 5 degrees, rotation of the liquid crystalmolecules 220 can be easily made and thus a response time can be moreimproved.

As described above, in the LCD 100 of the first embodiment, thenanocapsule liquid crystal layer 200 including the nanocapsules 230 thatare filled with the negative type liquid crystal molecules 220 and aredispersed in the buffer layer 210 is located between the first andsecond substrates 112 and 114, and thus a response time can be improvedcompared with that of the prior art.

Further, since the nanocapsule liquid crystal layer 200 does not have anoptically anisotropic initial arrangement, an alignment layer may not beneeded in the LCD and a rubbing process may also not be needed.

Further, in case that the nanocapsules 230 are dispersed in the bufferlayer 210 made of liquid crystal, the nanocapsule liquid crystal layer200 is formed in a printing method, coating method, or dispensingmethod. In case that the nanocapsules 230 are dispersed in the bufferlayer 210 made in a film type, the nanocapsule liquid crystal layer 200is formed in a lamination method. Accordingly, a process of forming agap between first and second substrates filled with a liquid crystallayer in the prior art can be eliminated, and a process of forming aseal pattern to prevent leakage of liquid crystal in the prior art canbe eliminated.

Thus, production efficiency can be improved.

Further, by eliminating the process of forming the alignment layer, incase that the LCD 100 is applied to a touch display device, curveddisplay device or flexible display device, light leakage, which occurswhen a rubbing axis is off a desired direction and thus arrangement ofliquid crystal molecules goes awry, can be reduced or prevented.

Thus, the LCD 100 can be applicable to a touch display device, curveddisplay device, or flexible display device.

Because the pixel and common electrodes 124 and 136 are formed with aslanted plane, an awry arrangement of the liquid crystal molecules 220due to a collision in the process of arranging the liquid crystalmolecules 220 can be reduced or prevented, and thus a light leakagecaused by an awry arrangement can be also reduced or prevented.

This can improve the transmittance of the LCD 100.

Further, since the liquid crystal molecules 220 are arranged in parallelat a tilt angle of 1 degree to 5 degrees with respect to the firstsubstrate 112, rotation of the liquid crystal molecules 220 can beeasily made and thus a response time can be further improved.

The LCD 100 of the first embodiment may be alternatively configured tohave a COT (color filter on transistor) structure, as illustrated inFIG. 6, where the thin film transistor T and the color filter 134 areformed together on the first substrate 112.

In this case, referring to FIGS. 3 and 6, a black matrix is formed on apassivation layer that is on the thin film transistor T, and has alattice shape. Red, green and blue color filters are formed on the blackmatrix and fill openings of the lattice of the black matrix in therespective pixel regions P. The pixel electrode 124 is formed on thecolor filter, and the common electrode 136 is formed on the secondsubstrate 114 and faces the pixel with the nanocapsule liquid crystallayer between the common electrode 136 and the pixel electrode 124.

Alternatively, as illustrated in FIG. 7, a COT type LCD may beconfigured not to have a second substrate, and in this case, the commonelectrode 136 may be formed on an inner surface of the second polarizingplate 130.

Second Embodiment

FIGS. 8A and 8B are schematic views illustrating an LCD according to asecond embodiment of the present invention. Explanations of partssimilar to parts of the above first embodiment may be omitted.

Referring to FIGS. 8A and 8B, the LCD (100 of FIG. 3) of the secondembodiment includes the liquid crystal panel 110 and the backlight unit160.

The liquid crystal panel 110 includes the first and second substrates112 and 114 facing each other, the nanocapsule liquid crystal layer 200,and the first and second polarizing plates 120 and 130 on the outersurfaces of the first and second substrates 112 and 114, respectively.

The liquid crystal panel 110 may be a vertical alignment (VA) modeliquid crystal panel. The thin film transistor (T of FIG. 3) and thepixel electrode 124 are formed on the inner surface of the firstsubstrate 112. The black matrix (132 of FIG. 3), the color filters 134,and the common electrode 136 are formed on the inner surface of thesecond substrate 114. An overcoat layer may be formed covering the blackmatrix 132 and the color filters 134.

The negative type nematic liquid crystal molecules 220 of thenanocapsule liquid crystal layer 200 are arranged perpendicularly to theelectric field that is perpendicular to the plane of the first andsecond substrates 112 and 114, and a refraction index in a directionperpendicular to the electric field is manifested.

Accordingly, to realize a maximum brightness, the polarizing axes of thefirst and second polarizing plates 120 and 130 are attached to each makea 45 degree angle with the liquid crystal molecules 220 perpendicular tothe electric field.

The backlight unit 160 supplies a scattering light close to a naturallight to the liquid crystal panel 110.

One of the particular components of this second embodiment is a phaseretardation film 170 between the second substrate 114 and the secondpolarizing plate 130.

The phase retardation film 170 may be formed of a λ/4 wave plate(quarter wave plate).

In this regard, as illustrated in FIG. 8A, when a voltage is off, ascattering light from the backlight unit 160 enters the first polarizingplate 120 and a linearly polarized light parallel with the polarizingaxis of the first polarizing plate 120 passes through and comes out fromthe first polarizing plate 120.

However, in the voltage-off state, the liquid crystal molecules 220 arearranged randomly, the liquid crystal molecules 220 and the nano capsule230 have different anisotropies in refractive index from each other.Accordingly, optically isotropic property is obtained.

Accordingly, the linearly polarized light from the first polarizingplate 120 passes through the nanocapsule liquid crystal layer 200 as is,and does not pass through the second polarizing plate 130 having thepolarizing axis perpendicular to the polarizing axis of the firstpolarizing plate 120. Thus, a black is displayed.

As illustrated in FIG. 8B, when voltages are applied to the pixelelectrode 124 and the common electrode 136, the liquid crystal molecules220 are arranged perpendicularly to the electric field between the pixeland common electrodes 124 and 136.

Accordingly, the nanocapsule liquid crystal layer 200 has an opticalanisotropy.

Accordingly, a scattering light from the backlight unit 160 entersthrough the first polarizing plate 120 so that a linearly polarizedlight comes out and other part is absorbed, and then a linearlypolarized light, which is parallel with the liquid crystal molecules220, out of the linearly polarized light coming out from the firstpolarizing light 120, passes through the liquid crystal layer 200.

Then, the linearly polarized light passing through the liquid crystallayer 200 is modified by the phase retardation film 170 into acircularly polarized light, and then the circularly polarized light ismodified into a linearly polarized light, which is parallel with thepolarizing axis of the second polarizing plate 130, while passingthrough the second polarizing plate 130. Thus, a white is displayed.

In this regard, since the LCD 100 of the second embodiment includes thephase retardation film 170 between the second substrate 114 and thesecond polarizing plate 130, a light leakage can be reduced orprevented, and non-uniformity of brightness and image can be reduced orprevented.

In more detail, the negative type liquid crystal molecules 220 randomlyarranged collide one another without directivity in the process that themolecules 220 are arranged perpendicularly to the electric field inducedbetween the pixel and common electrodes 124 and 136.

Because of this collision among the liquid crystal molecules 220, theliquid crystal molecules 220 are not arranged in parallel with oneanother, and this causes a light leakage. Further, this light leakagecauses non-uniformity of brightness and image.

However, according to the phase retardation film 170 between the secondsubstrate 114 and the second polarizing plate 130 in the secondembodiment, the linearly polarized light from the nanocapsule liquidcrystal layer 200 is modified into the circularly polarized light, whichthen enters the second polarizing plate 130. Accordingly, light leakagecan be reduced or prevented, and thus non-uniformity of brightness andimage can be reduced or prevented.

As described above, the response time can be improved, and the processof forming an alignment layer, the process of forming a cell gap, theprocess of forming a seal pattern can be eliminated, and thus productionefficiency can be improved.

Further, the LCD 100 can be applied to a touch display device, curveddisplay device, or flexible display device.

Particularly, by providing the phase retardation film 170 between thesecond substrate 114 and the second polarizing plate 130, the linearlypolarized light is modified by the phase retardation film 170 into acircularly polarized light, which then enters the second polarizingplate 130. Accordingly, a light leakage can be reduced or prevented.Thus, non-uniformity of brightness and image due to such a light leakagecan be reduced or prevented.

The LCD 100 of the second embodiment may be alternatively configured tohave a COT (color filter on transistor) structure, as illustrated inFIG. 9, where the thin film transistor T and the color filter 134 areformed together on the first substrate 112.

In this case, referring to FIGS. 3 and 9, a black matrix is formed on apassivation layer that is on the thin film transistor T, and has alattice shape. Red, green and blue color filters are formed on the blackmatrix and fill openings of the lattice of the black matrix in therespective pixel regions P. The pixel electrode 124 is formed on thecolor filter, and the common electrode 136 is formed on the secondsubstrate 114 and faces the pixel with the nanocapsulc liquid crystallayer between the common electrode 136 and the pixel electrode 124.

Alternatively, as illustrated in FIG. 10, a COT type LCD may beconfigured not to have a second substrate, and in this case, the commonelectrode 136 may be formed on an inner surface of the phase retardationfilm 170.

Third Embodiment

FIG. 11A is a schematic view illustrating an LCD according to a thirdembodiment of the present invention. Explanations of parts similar toparts of the above first and second embodiments may be omitted.

Referring to FIG. 11A, the LCD (100 of FIG. 3) of the third embodimentincludes the liquid crystal panel 110 and the backlight unit 160.

The liquid crystal panel 110 includes the first and second substrates112 and 114 facing each other, the nanocapsule liquid crystal layer 200,and the first and second polarizing plates 120 and 130 on the outersurfaces of the first and second substrates 112 and 114, respectively.

The liquid crystal panel 110 may be a vertical alignment (VA) modeliquid crystal panel. The thin film transistor (T of FIG. 3) and thepixel electrode 124 are formed on the inner surface of the firstsubstrate 112. The black matrix (132 of FIG. 3), the color filters 134,and the common electrode 136 are formed on the inner surface of thesecond substrate 114. An overcoat layer may be formed covering the blackmatrix 132 and the color filters 134.

The pixel electrode 124 and the common electrode 136 have first andsecond slits 180 a and 180 b, respectively.

In other words, the pixel electrodes 124 are spaced apart from eachother to form the first slits 180 a, and similarly, the commonelectrodes 136 are spaced apart from each other to form the second slits180 b.

The first slit 180 a has a width much less than a width of the pixelelectrode 124. In other words, the width of the pixel electrode 124 is afew to a few tens of times the width of the first slit 180 a.

The first and second slits 180 a and 180 a alternate. It is preferredthat each first slit 180 a is located at a center portion of thecorresponding common electrode 136 that is between the neighboringsecond slits 180 b, and each second slit 180 b is located at a centerportion of the corresponding pixel electrode 124 that is between theneighboring first slits 180 a.

Accordingly, when voltages are applied to the pixel electrode 124 andthe common electrode 136, a fringe electric field inclined from adirection perpendicular to the plane of the first and second substrates112 and 114 is realized.

Accordingly, the negative type liquid crystal molecules 220 are arrangedperpendicularly to the fringe electric field between the pixel andcommon electrodes 124 and 136, and a refraction index perpendicular tothe fringe electric field is manifested.

Accordingly, the nanocapsule liquid crystal layer 200 has an opticalanisotropy.

Accordingly, a scattering light from the backlight unit 160 entersthrough the first polarizing plate 120 so that a linearly polarizedlight comes out and other part is absorbed, and then a linearlypolarized light, which is parallel with the liquid crystal molecules220, out of the linearly polarized light coming out from the firstpolarizing light 120, passes through the liquid crystal layer 200.

Then, a linearly polarized light, which is parallel with the polarizingaxis of the second polarizing plate 130, out of the linearly polarizedlight coming out from the nanocapsule liquid crystal layer 200 passesthrough the second polarizing plate 130, and thus a white is displayed.

In this regard, since the LCD 100 of the third embodiment includes thepixel electrode 124 and the common electrode 136 having the first slit180 a and the second slit 180 b, respectively, and generates the fringeelectric field between the pixel and common electrodes 124 and 136, thenegative type liquid crystal molecules 220 are arranged perpendicularlyto the fringe electric field. Accordingly, the liquid crystal molecules220 can be arranged more uniformly in parallel.

In other words, the liquid crystal molecules 220 randomly arranged aremore easily rotated and arranged because of the fringe electric field.

Accordingly, an awry arrangement of the liquid crystal molecules 220because of collision among the molecules 220 in the process that themolecules 220 are arranged perpendicularly can be reduced or prevented,and thus a light leakage due to the awry arrangement can be reduced orprevented.

Further, transmittance of the LCD 100 can be improved.

Further, since the liquid crystal molecules 220 are arrangedperpendicularly to the fringe electric field between the pixel andcommon electrodes 124 and 136, rotation is more easily made and thusresponse time is improved.

As described above, the response time can be improved, and the processof forming an alignment layer, the process of forming a cell gap, theprocess of forming a seal pattern can be eliminated, and thus productionefficiency can be improved.

Further, the LCD 100 is applicable to a touch display device, curveddisplay device, or flexible display device.

Particularly, since the pixel electrode 124 and the common electrode 136are configured to have the first slit 180 a and the second slit 180 b,respectively, and generate the fringe electric field between the pixeland common electrodes 124 and 136, the negative type liquid crystalmolecules 220 are arranged in parallel with one another andperpendicularly to the fringe electric field, and thus a light leakagecan be reduced or prevented.

Thus, non-uniformity of brightness and image due to the light leakagecan be reduced or prevented.

Since the liquid crystal molecules 220 have substantially uniform andconsistent arrangement corresponding to the second slit 180 b, when thesecond slit 180 b is configured to have a bent shape verticallysymmetrical in the pixel region P, as illustrated in FIG. 11B, fourdifferent domains at up, down, left and right sides in each pixel regionP can be obtained. In this case, the second slit 180 b is bent at acenter portion of the pixel region P, and the first slit 180 a is bentlike the second slit 180 b.

Alternatively, even though not shown in the drawings, when a pluralityof second slits 180 b are configured to be located and bent to bevertically symmetrical in a pixel region, multi-domains that are fourtimes the number of the plurality of second slits 180 b may be formed ineach pixel region P.

Fourth Embodiment

FIG. 12A is a schematic view illustrating an LCD according to a fourthembodiment of the present invention. Explanations of parts similar toparts of the above first to third embodiments may be omitted.

Referring to FIG. 12A, the LCD (100 of FIG. 3) of the fourth embodimentincludes the liquid crystal panel 110 and the backlight unit 160.

The liquid crystal panel 110 includes the first and second substrates112 and 114 facing each other, the nanocapsule liquid crystal layer 200,and the first and second polarizing plates 120 and 130 on the outersurfaces of the first and second substrates 112 and 114, respectively.

The liquid crystal panel 110 may be a vertical alignment (VA) modeliquid crystal panel. The thin film transistor (T of FIG. 3) and thepixel electrode 124 are formed on the inner surface of the firstsubstrate 112. The black matrix (132 of FIG. 3), the color filters 134,and the common electrode 136 are formed on the inner surface of thesecond substrate 114. An overcoat layer may be formed covering the blackmatrix 132 and the color filters 134.

The pixel electrode 124 has a pixel slit 190 a, and a common protrusion190 b is formed on the common electrode 136.

In other words, the pixel electrodes 124 are spaced apart from eachother to form the pixel slits 190 a, and the common protrusions 190 bare spaced apart from each other on the common electrode 136.

The common protrusion 190 b may have a triangular shape in across-section. Alternatively, the common electrode 190 b may have othershapes, for example, a semi-circular or semi-elliptical shape.

The common protrusions 190 b and the pixel slits 190 a are arrangedalternately and parallel with each other in a pixel region in a planview, and are arranged alternately in a zigzag form with the liquidcrystal layer 200 therebetween in a cross-sectional view.

In other words, the pixel slit 190 a is located corresponding to aseparate region between the neighboring common protrusions 190 b, andeach common protrusion 190 b are located at a center portion of thecorresponding pixel electrode 124 that is between the neighboring pixelslits 190 a.

Accordingly, when voltages are applied to the pixel electrode 124 andthe common electrode 136, a fringe electric field inclined from adirection perpendicular to the plane of the first and second substrates112 and 114 is realized.

Accordingly, the negative type liquid crystal molecules 220 are arrangedperpendicularly to the fringe electric field between the pixel andcommon electrodes 124 and 136, and a refraction index perpendicular tothe fringe electric field is manifested.

Accordingly, the nanocapsule liquid crystal layer 200 has an opticalanisotropy.

Accordingly, a scattering light from the backlight unit 160 entersthrough the first polarizing plate 120 so that a linearly polarizedlight comes out and other part is absorbed, and then a linearlypolarized light, which is parallel with the liquid crystal molecules220, out of the linearly polarized light coming out from the firstpolarizing light 120, passes through the liquid crystal layer 200.

Then, a linearly polarized light, which is parallel with the polarizingaxis of the second polarizing plate 130, out of the linearly polarizedlight coming out from the nanocapsule liquid crystal layer 200 passesthrough the second polarizing plate 130, and thus a white is displayed.

In this regard, since the LCD 100 of the fourth embodiment includes thepixel electrode 124 and the common electrode 136 having the pixel slit190 a and the common protrusion 190 b, respectively, and generates thefringe electric field between the pixel and common electrodes 124 and136, the negative type liquid crystal molecules 220 are arrangedperpendicularly to the fringe electric field. Accordingly, the liquidcrystal molecules 220 can be arranged more uniformly in parallel.

In other words, the liquid crystal molecules 220 randomly arranged aremore easily rotated and arranged because of the fringe electric field.

Accordingly, an awry arrangement of the liquid crystal molecules 220because of collision among the molecules 220 in the process that themolecules 220 are arranged perpendicularly can be reduced or prevented,and thus light leakage due to the awry arrangement can be reduced orprevented.

Further, transmittance of the LCD 100 can be improved.

Further, since the liquid crystal molecules 220 are arrangedperpendicularly to the fringe electric field between the pixel andcommon electrodes 124 and 136, rotation is more easily made and thusresponse time is improved.

As described above, the response time can be improved, and the processof forming an alignment layer, the process of forming a cell gap, theprocess of forming a seal pattern can be eliminated, and thus productionefficiency can be improved.

Further, the LCD 100 can be applied to a touch display device, curveddisplay device, or flexible display device.

Particularly, since the pixel electrode 124 and the common electrode 136are configured to have the pixel slit 190 a and the common protrusion190 b, respectively, and generate the fringe electric field between thepixel and common electrodes 124 and 136, the negative type liquidcrystal molecules 220 are arranged in parallel with one another andperpendicularly to the fringe electric field, and thus light leakage canbe prevented.

Thus, non-uniformity of brightness and image due to the light leakagecan be reduced or prevented.

Since the liquid crystal molecules 220 have substantially uniform andconsistent arrangement corresponding to the common protrusion 190 b,when the common protrusion 190 b is configured to have a bent shapevertically symmetrical in the pixel region P, as illustrated in FIG.12B, four different domains at up, down, left and right sides in eachpixel region P can be obtained. In this case, the pixel slit 190 a isbent like the common protrusion 190 b.

Fifth and sixth embodiments of the present invention, which will now bedescribed, relate to a reflective type LCD.

Fifth Embodiment

FIG. 13 is a perspective view illustrating an LCD according to the fifthembodiment of the present invention. Explanations of parts similar toparts of the above first to fourth embodiments may be omitted.

Referring to FIG. 13, the LCD 100 includes a liquid crystal panel 110, apolarizing plate 130, a phase retardation plate 175, and a reflectionplate 140. The LCD 100 using the reflection plate 140 is referred to asa reflective type LCD.

The liquid crystal panel 110 includes a first substrate 112, a secondsubstrate 114, and a nanocapsule liquid crystal layer 200 between thefirst and second substrates 112 and 114.

The first substrate 112 is referred to as a lower substrate or an arraysubstrate. A plurality of gate lines 116 and a plurality of data lines118 cross each other on an inner surface of the first substrate 112 todefine a plurality of pixel regions P.

A thin film transistor T is formed near the crossing portion of the gateand data lines 116 and 118, and is connected to a pixel electrode 124 inthe pixel region P.

The second substrate 114 is referred to as an upper substrate or a colorfilter substrate. A black matrix 132 is on an inner surface of thesecond substrate 114, and shields a non-display element such as the gateline 116, the data line 118, and the thin film transistor T exposing thepixel electrode 124. The black matrix 132 has a lattice shapesurrounding the pixel region P.

Red, green and blue color filters 134 fill openings of the black matrix132 corresponding to the respective pixel regions P. A common electrode136 covers the black matrix 132 and the color filters 134.

Even though not shown in the drawings, the first substrate 112 has anarea greater than that of the second substrate 114 so that a peripheralportion of the first substrate 112 is exposed outside the secondsubstrate 114. In the exposed portion of the first substrate 112, datapads 118 a connected to the respective data lines 118, and gate pads(not shown) connected to the respective gate lines 116 are formed.

When a gate line 116 is selected and supplied with a turn-on gate signali.e., high-level gate signal, the thin film transistor T connected tothe selected gate line 116 is turned on and an image data signal istransferred to the pixel electrode 124 through the data line 118.Accordingly, an electric field is induced between the pixel electrode124 and the common electrode 136 and controls liquid crystal molecules220 of the nanocapsule liquid crystal layer 200, and thus lighttransmittance is changed to display images.

The polarizing plate 130 is attached on an outer surface of the secondsubstrate 114.

The phase retardation plate 175 is located between the second substrate114 and the polarizing plate 130. The phase retardation plate 175 may bea λ/4 plate (a quarter wave plate).

It is preferred that three refractive indices nx, ny and nz of the phaseretardation plate 175 meet the following relation: nx=ny>nz. The phaseretardation plate 175 and the polarization plate 130 may be formed asone body.

The reflection plate 140 is located on an outer surface of the firstsubstrate 112. The reflection plate 140 reflects an external light fromthe outside into the liquid crystal panel 110.

The reflection plate 140 may be fat lied of a metal material such asaluminum (Al) to increase reflectance.

Alternatively, the reflection plate 140 may be located between the firstsubstrate 112 and the nanocapsule liquid crystal layer 200. In thiscase, the reflection plate 140 may function as a reflection electrodeand have an embossing pattern for diffused reflection.

The nanocapsule liquid crystal layer 200 is an optically isotropic typeliquid crystal layer in a normal state. Accordingly, when no electricfield between the pixel electrode 124 and the common electrode 136 isapplied to the nanocapsule liquid crystal layer 200, the nanocapsuleliquid crystal layer 200 is optically isotropic, and when an electricfield is applied, the nanocapsule liquid crystal layer 200 has abirefringence property in a direction perpendicular to the appliedelectric field.

In other words, in case that the liquid crystal molecules 220 arenegative type nematic liquid crystal molecules, the liquid crystalmolecules 220 are arranged perpendicularly to an electric field togenerate a birefringence. In case that the liquid crystal molecules 220are positive type nematic liquid crystal molecules, the liquid crystalmolecules 220 are arranged in parallel with an electric field togenerate a birefringence property.

Accordingly, when an electric field is applied, the nanocapsule liquidcrystal layer 200 has an optically uniaxial property

In more detail, the liquid crystal molecules 220 are contained withinthe capsule 230 having a nanosize, and the liquid crystal molecules 220are irregularly arranged in the nanocapsule 230.

The nanocapsule 230 may have about 5% to about 95% of a total volume ofthe nanocapsule liquid crystal layer 200, and preferably, may have about25% to about 65% of the total volume of the nanocapsule liquid crystallayer 200. The buffer layer 210 occupies the rest of the total volume.

The buffer layer 210 may be made of a transparent or semi-transparentmaterial and have water-solubility, fat-solubility, or mixture ofwater-solubility and fat-solubility. The buffer layer 210 may be heatcured or UV cured.

The buffer layer 210 may have an additive to increase strength andreduce curing time.

The nanocapsule 230 may have a diameter of about 1 nm to about 320 nm,and preferable, about 30 nm to about 100 nm.

Since the nanocapsule 230 has a diameter less than any wavelengths ofvisible light, there occurs substantially no optical change due torefractive index, and optically isotropic property can be obtained.Further, scattering of visible light can be reduced or minimized.

Particularly, when the nanocapsule 230 is formed with a diameter ofabout 100 nm or less, high contrast ratio can be obtained.

A thickness of the nanocapsule liquid crystal layer 200 (i.e., a cellgap) is preferably about 1 um to about 10 um, and more preferably about2 um to about 5 um.

In case that the cell gap is 2 um or less, it is difficult to externallyrecognize a difference in light transmittance.

In case that the cell gap is Sum or more, a distance between electrodesis great, and thus high power consumption is required. Further, anoverall thickness of the liquid crystal panel 110 increases, and thus itis difficult to provide an LCD having lightweight and thin profile.

The irregularly arranged liquid crystal molecules 220 and thenanocapsule 230 have different refractive indices, and thus a lightscattering may be caused at the interface therebetween. Accordingly,when light passes through the interface, the light is scattered andbecomes opaque in milk white.

However, when an electric field is applied to the nanocapsule liquidcrystal layer 200, the liquid crystal molecules 220 filling thenanocapsule 230 are regularly arranged.

In this state, the refractive index of the liquid crystal molecules 220is changed. In order to reduce or minimize a light scattering at theinterface between the nanocapsule 230 and the liquid crystal molecules220, the nanocapsule 230 and the regularly arranged liquid crystalmolecules 220 are formed such that they have refractive indices that aresubstantially close to each other, Therefore, the nanocapsule liquidcrystal layer 200 can be seen transparent.

In this case, it is preferred that a difference between the refractiveindex of the nanocapsule 220 and the refractive index of the liquidcrystal molecule 220 is within about ±0.1. The average refractive index(n) of the liquid crystal molecule 220 may be defined as follows:n=[(ne+2*no)/3] (where ne is a refractive index of a major axis of theliquid crystal molecule 220, and no is a refractive index of a minoraxis of the liquid crystal molecule 220).

Accordingly, the LCD 100 including the nanocapsule liquid crystal layer200 can be used as a display device, with its transmittance changingaccording to a variation of the voltage applied.

Further, since the nanocapsule liquid crystal layer 200 does not have aninitial alignment to be optically anisotropic, alignment of liquidcrystal molecules may not be required, and thus no alignment layer maybe needed in the LCD 100, and also, processes for forming an alignmentlayer such as rubbing may not be needed.

Further, in case that the nanocapsules 230 are dispersed in the bufferlayer 210 made of, for example, liquid crystal, the nanocapsule liquidcrystal layer 200 may be formed, for example, by a printing method,coating method, or dispensing method. In case that the nanocapsules 230are dispersed in the buffer layer 210 made in a film type, thenanocapsule liquid crystal layer 200 may be formed, for example, by alamination method. Accordingly, a process of forming a gap between thefirst and second substrates filled with the liquid crystal layer (50 ofFIG. 1) in the prior art can be eliminated, and a process of forming theseal pattern (70 of FIG. 1) in the prior art can be eliminated.

Therefore, production efficiency can be improved.

Further, even when an external force such as a user's touch is appliedto the LCD 100 of the embodiment, the liquid crystal molecules 220 arein the nanocapsule 230 having a size less than the wavelength of visiblelight, thus there is substantially no influence of visible light, andthus a light leakage due to the external force can be reduced orprevented.

Accordingly, in case that the LCD 100 of the embodiment is applied to aflexible display device, even when an external force is applied to theLCD 100, because of the nanocapsule 230 having a size less than thewavelength of visible light, a light leakage due to the external forcecan be reduced or prevented.

Further, when the electric field is induced between the first and secondsubstrates 112 and 114, the liquid crystal molecules 220 are dynamicallyrotated, and thus response speed can be fast.

FIGS. 14A and 14B are schematic views illustrating an image displayprinciple of the LCD according to the fifth embodiment of the presentinvention, and FIGS. 15A and 15B are schematic views illustratingvariation of light in the states of FIGS. 14A and 14B, respectively.

Referring to FIGS. 14A to 15B, the liquid crystal panel 110 includes thepixel electrode 124 and the common electrode 136 to generate a verticalelectric field. The liquid crystal molecules 220 are negative typenematic liquid crystal molecules.

In the LCD 100, the polarizing plate 130 is located close to the sideupon which an external light is incident, and the phase retardationplate 175, the liquid crystal panel 110 and the reflection plate 140 aresequentially arranged below the polarizing plate 130.

The phase retardation plate 120 may be between the second substrate 114and the nanocapsule liquid crystal layer 200. The reflection plate 140may be between the first substrate 112 and the nanocapsule liquidcrystal layer 200.

The thin film transistor T and the pixel electrode 124 are formed on aninner surface of the first substrate 112. The black matrix 132, thecolor filter 134 and the common electrode 136 are formed on an innersurface of the second substrate 114.

The liquid crystal molecules 220 are arranged perpendicularly to anelectric field that is vertical to the first and second substrates 112and 114, and a refractive index in a direction perpendicular to theelectric field is manifested.

Referring to FIGS. 14A and 15A, when no voltage is applied to the liquidcrystal panel 110, the liquid crystal molecules 220 are arrangedrandomly, the liquid crystal molecules 220 and the nano capsule 230 havedifferent anisotropies in refractive index from each other. Accordingly,optically isotropic property is obtained.

Accordingly, out of an external light, the polarizing plate 130transmits a first linearly polarized light parallel with a polarizingaxis of the polarizing plate 130 and absorbs other light. The firstlinearly polarized is modified into a circularly polarized light (e.g.,a left-hand circularly polarized light) while passing through the phaseretardation plate 175.

Then, the left-hand circularly polarized light passes through thenanocapsule liquid crystal layer 200 as is, and then is reflected by thereflection plate 140 and modified into a right-hand circularly polarizedlight.

The right-hand circularly polarized light passes through the nanocapsuleliquid crystal layer 200 as is, and then enters the phase retardationplate 175. While passing through the phase retardation plate 175, theright-hand circularly polarized light is modified into a second linearlypolarized light that is perpendicular to the first linearly polarizedlight.

The second polarized light does not pass through the polarizing plate130, and thus a black is displayed.

Referring to FIGS. 14B and 15B, when a voltage is applied to the pixelelectrode 124 and the common electrode 136, the liquid crystal molecules220 are arranged perpendicularly to the electric field between the pixeland common electrodes 124 and 136. Accordingly, optically anisotropicproperty is obtained.

Accordingly, out of an external light, the polarizing plate 130transmits a first linearly polarized light parallel with a polarizingaxis of the polarizing plate 130 and absorbs other light. The firstlinearly polarized is modified into a left-hand circularly polarizedlight while passing through the phase retardation plate 175.

Then, while passing through the nanocapsule liquid crystal layer 200,the left-hand circularly polarized light is phase-retarded and thus asecond linearly polarized light perpendicular to the first linearlypolarized light comes out from the nanocapsule liquid crystal layer 200.

Then, the second linearly polarized light is reflected by the reflectionplate 140, and then is phase-retarded passing through the nanocapsuleliquid crystal layer 200. Accordingly, a right-hand circularly polarizedlight comes out from the nanocapsule liquid crystal layer 200, and thenis modified into the first linearly polarized light while passingthrough the phase retardation plate 175.

Then, the first linearly polarized light passes through the polarizingplate 130, and thus a white is displayed.

Sixth Embodiment

FIGS. 16A and 16B are schematic views illustrating an image displayprinciple of the LCD according to the sixth embodiment of the presentinvention. Explanations of parts similar to parts of the first to fifthembodiments may be omitted.

Referring to FIGS. 16A and 16B, the liquid crystal panel 110 includesthe pixel electrode 124 and the common electrode 136 to generate anin-plane electric field which is substantially parallel with the firstand second substrates 112 and 114. The liquid crystal molecules 220 arepositive type nematic liquid crystal molecules.

In the LCD 100, the polarizing plate 130 is located close to the sideupon which an external light is incident, and the phase retardationplate 175, the liquid crystal panel 110 and the reflection plate 140 aresequentially arranged below the polarizing plate 130.

The phase retardation plate 120 may be provided between the secondsubstrate 114 and the nanocapsule liquid crystal layer 200. Thereflection plate 140 may be provided between the first substrate 112 andthe nanocapsule liquid crystal layer 200.

The liquid crystal panel 110 includes the first and second substrates112 and 114, and the nanocapsule liquid crystal layer 200 therebetween.The liquid crystal panel 110 is an IPS (in-plane switching) type panel,in which the thin film transistor T, the pixel electrode 124, and thecommon electrode 136 are formed on an inner surface of the firstsubstrate 112. The black matrix 132 and the color filter 134 are formedon an inner surface of the second substrate 114. The pixel and commonelectrode 112 and 114 on the same substrate 112 generates an in-planeelectric field parallel with the first and second substrates 112 and114.

The liquid crystal molecules 220 are arranged parallel to the in-planeelectric field that is parallel to the first and second substrates 112and 114, and a refractive index in a direction parallel to the electricfield is manifested.

Referring to FIG. 16A, when no voltage is applied to the liquid crystalpanel 110, an external light is finally blocked by the polarizing plate130, and thus a black is displayed.

Referring to FIG. 16B, when a voltage is applied to the pixel electrode124 and the common electrode 136, the liquid crystal molecules 220 areuniformly arranged parallel to the electric field between the pixel andcommon electrodes 124 and 136.

Accordingly, an external light passes through the polarizing plate 130,phase retardation plate 175, and the nanocapsule liquid crystal layer200, then is reflected by the reflection plate 140, then passes throughthe nanocapsule liquid crystal layer 200, the phase retardation plate175 and the polarizing plate 130, and thus a white is displayed.

The reflective type LCD 100 according to the above fifth or sixthembodiment may be alternatively configured to have a COT (color filteron transistor) structure, where the thin film transistor T and the colorfilter 134 are formed together on the first substrate 112.

In this case, a black matrix is formed on a passivation layer that is onthe thin film transistor T, and has a lattice shape. Red, green and bluecolor filters are formed on the black matrix and fill openings of thelattice of the black matrix in the respective pixel regions P. The pixelelectrode 124 is formed on the color filter, and the common electrode136 is formed on the first substrate 112 or second substrate 114corresponding to the pixel electrode 124.

Alternatively, a COT type LCD may be configured not to have a secondsubstrate, and in this case, the common electrode 136 of the fifthembodiment may be formed on an inner surface of the phase retardationplate 175.

In the reflective type LCD as above, by using the nanocapsule liquidcrystal layer 200, where the nanocapsule 230 each filled with therandomly arranged nematic liquid crystal molecules 220 are dispersed inthe buffer layer 210, between the first and second substrates 112 and114, a response time can be fast compared to the prior art LCD.

Further, since the nanocapsule liquid crystal layer 200 does not have aninitial alignment to be optically anisotropic, alignment of liquidcrystal molecules may not be required, and thus no alignment layer maybe needed in the LCD 100, and also, processes for forming an alignmentlayer such as rubbing may not be needed.

Further, in case that the nanocapsules 230 are dispersed in the bufferlayer 210 made of, for example, liquid crystal, the nanocapsule liquidcrystal layer 200 may be formed, for example, by a printing method,coating method, or dispensing method. In case that the nanocapsules 230are dispersed in the buffer layer 210 made in a film type, thenanocapsule liquid crystal layer 200 may be formed, for example, by alamination method. Accordingly, a process of forming a gap between thefirst and second substrates filled with the liquid crystal layer in theprior art can be eliminated, and a process of forming the seal patternin the prior art can be eliminated.

Therefore, production efficiency can be improved.

Further, even when an external force such as a user's touch is appliedto the LCD 100 of the embodiment, the liquid crystal molecules 220 arein the nanocapsule 230 having a size less than the wavelength of visiblelight, thus there is substantially no influence of visible light, andthus light leakage due to the external force can be prevented.

Accordingly, in case that the LCD 100 of the embodiment is applied to aflexible display device, even when an external force is applied to theLCD 100, because of the nanocapsule 230 having a size less than thewavelength of visible light, light leakage due to the external force canbe prevented.

Seventh to Eleventh embodiments of the present invention, which will nowbe described, relate to a flexible type LCD.

Seventh to Ninth Embodiments

FIGS. 17A and 17B are schematic views illustrating an image displayprinciple of an LCD according to a seventh embodiment of the presentinvention, and FIGS. 17C and 17D are schematic views illustrating an LCDaccording to eighth and ninth embodiments of the present invention,respectively. Explanations of parts similar to parts of the first tosixth embodiments may be omitted.

Referring to FIGS. 17A-17B, the flexible type LCD includes a liquidcrystal panel 110 and a backlight unit 160.

The liquid crystal panel 110 includes a nanocapsule liquid crystal layer200 on a substrate 112.

The substrate 112 is referred to as an array substrate. A plurality ofgate lines and a plurality of data lines cross each other on an innersurface of the first substrate to define a plurality of pixel regions P.A thin film transistor is formed near the crossing portion of the gateand data lines. A black matrix is formed on the thin film transistorwith a passivation layer therebetween, and has a lattice shape exposingthe pixel regions. Red, green and blue color filters 134 fill openingsof the black matrix 132 corresponding to the respective pixel regions.

A pixel electrode 124 connected to the thin film transistor and a commonelectrode 136 spaced apart from the pixel electrode 124 are formed onthe color filters 134.

Liquid crystal molecules 220 of the nanocapsule liquid crystal layer 200are driven by an in-plane electric field between the pixel and commonelectrodes 124 and 136.

A polarizing plate 130 is attached onto the nanocapsule liquid crystallayer 200.

A backlight unit 160 is below the liquid crystal panel 110 and supplieslight to the liquid crystal panel 110.

The backlight unit 160 includes an LED assembly 129 along a lengthdirection of a side of the backlight unit 160, a reflective polarizingfilm 127, a reflection plate 125 in white or silver color, a light guideplate 123 and at least one optical sheet 121.

The LED assembly 129 is located facing a side of the light guide plate123 upon which the light is incident, and includes a plurality of LEDs129 a and a PCB (printed circuit board) 129 b on which the plurality ofLEDs 129 a are mounted, with being spaced apart from each other.

The reflective polarizing film 127 is located on the front of the LEDs129 a. Out of light emitted from the LEDs 129 a, the reflectivepolarizing film 127 transmits a predetermined polarized light, andreflects and recycles other part, and thus light efficiency of theflexible type LCD can be improved.

The reflective polarizing film 127 may be formed using a polarizerhaving a predetermined polarizing axis embedded in a laminationstructure of dielectric thin films having different refractive indices,or using a wire grid polarizer in which fine line type metal patterns ofa high reflective material, such as aluminum (Al), silver (Ag) orchromium (Cr) are arranged in parallel along a direction on a base film.

The reflective polarizing film 127 has a polarizing axis perpendicularto the polarizing axis of the polarizing plate 130.

Accordingly, all light emitted from the LED assembly 129 are supplied tothe liquid crystal panel 110 substantially without loss of light.

In other words, out of the light from the LED assembly 129, a portion ofthe light having the same polarizing axis as the reflective polarizingfilm 127 is transmitted, and the other portion is reflected by thereflective polarizing film 127. A first polarized light PL1 out of thelight emitted from the LED 129 a is transmitted by the reflectivepolarizing plate 127 and enters into the light guide plate 123 via thelight incidence surface of the light guide plate 123. A second polarizedlight PL2, which is perpendicular to the first polarized light PL1, outof the light from the LED 129 a is reflected by the reflectivepolarizing film 127 and is recycled into a scattering light.

A first polarized light PL1 out of the recycled scattering light istransmitted by the reflective polarizing film 127, and a secondpolarized light PL2 out of the recycled scattering light is recycledagain into a scattering light. Accordingly, light efficiency can beimproved.

A specific linearly polarized light entering the light guide plate 123travels in the light guide plate 123 and evenly spreads over a largearea of the light guide plate 123, and thus a plane light is supplied tothe liquid crystal panel 110.

The light guide plate 123 may include a specific-shaped pattern at abottom surface to supply a uniform plane light.

The reflection plate 125 is located below the light guide plate 123, andreflects light coming out from the bottom surface of the light guideplate 123 to the liquid crystal panel 110, and thus brightness of lightis improved.

The at least one optical sheet 121 may include a diffusion sheet, and atleast one light concentration sheet. The at least one optical sheet 121diffuses and/or concentrates light to supply more uniform plane light tothe liquid crystal panel 110.

A cold cathode fluorescent lamp (CCFL), or external electrodefluorescent lamp (EEFL) may be uses as a light source instead of the LED129 a.

The liquid crystal panel 110 and the backlight unit 160 are attached toeach other using a lamination process. In this process, an adhesive isinterposed between the liquid crystal panel 110 and the backlight unit120 to eliminate an air gap therebetween, and thus loss of light due tothe air gap can be reduced or prevented.

The nanocapsule liquid crystal layer 200 is an optically isotropic typeliquid crystal layer in a normal state. Accordingly, when no electricfield between the pixel electrode 124 and the common electrode 136 isapplied to the nanocapsule liquid crystal layer 200, the nanocapsuleliquid crystal layer 200 is optically isotropic, and when an electricfield is applied, the nanocapsule liquid crystal layer 200 has abirefringence property in a direction perpendicular to the appliedelectric field

In other words, in case that the liquid crystal molecules 220 arenegative type nematic liquid crystal molecules, the liquid crystalmolecules 220 are arranged perpendicularly to an electric field togenerate a birefringence property. In case that the liquid crystalmolecules 220 arc positive type nematic liquid crystal molecules, theliquid crystal molecules 220 are arranged in parallel with the electricfield to generate a birefringence property.

Accordingly, when an electric field is applied, the nanocapsule liquidcrystal layer 200 has an optically uniaxial property

In more detail, the liquid crystal molecules 220 are contained withinthe capsule 230 having a nanosize, and the liquid crystal molecules 220are irregularly arranged in the nanocapsule 230.

The nanocapsule 230 may have about 5% to about 95% of a total volume ofthe nanocapsule liquid crystal layer 200, and preferably, may have about25% to about 65% of the total volume of the nanocapsule liquid crystallayer 200. The buffer layer 210 occupies the rest of the total volume.

The buffer layer 210 may be made of a transparent or semi-transparentmaterial and have water-solubility, fat-solubility, or mixture ofwater-solubility and fat-solubility. The buffer layer 210 may be heatcured or UV cured.

The buffer layer 210 may have an additive to increase strength andreduce curing time.

The nanocapsule 230 may have a diameter of about 1 nm to about 320 nm,and preferable, about 30 nm to about 100 nm.

Since the nanocapsule 230 has a diameter less than any wavelengths ofvisible light (i.e., with a diameter of about 320 nm or less), thereoccurs substantially no optical change due to refractive index, andoptically isotropic property can be obtained. Further, scattering ofvisible light can be reduced or minimized.

Particularly, when the nanocapsule 230 is formed with a diameter ofabout 100 nm or less, high contrast ratio can be obtained.

A thickness of the nanocapsule liquid crystal layer 200 (i.e., a cellgap) is preferably about 1 um to about 10 um, and more preferably about2 um to about 5 um.

In case that the cell gap is 2 um or less, it is difficult to externallyrecognize a difference in light transmittance.

In case that the cell gap is Sum or more, a distance between electrodesis great, and thus high power consumption is required. Further, anoverall thickness of the liquid crystal panel 110 increases, and thus itis difficult to provide an LCD having lightweight and thin profile.

Referring to FIG. 17A, when no voltage is applied to the liquid crystalpanel 110, the liquid crystal molecules 220 are arranged randomly, theliquid crystal molecules 220 and the nano capsule 230 have differentanisotropies in refractive index from each other. Accordingly, opticallyisotropic property is obtained.

Accordingly, a linearly polarized light emitted from the backlight unit160 passes through the nanocapsule liquid crystal layer 200 as is, andthen does not pass through the polarizing plate 130 perpendicular to thepolarizing axis of the linearly polarized light from the backlight unit160. Thus, a black is displayed.

Referring to FIG. 17B, when a voltage is applied between the pixelelectrode 124 and the common electrode 136, the liquid crystal molecules220 are arranged parallel with the electric field between the pixel andcommon electrodes 124 and 136. Accordingly, a linearly polarized light,parallel with the liquid crystal molecules 220, out of the linearlypolarized light emitted from the backlight unit 160 passes through thenanocapsule liquid crystal layer 200.

Then, a linearly polarized light, parallel with the polarizing axis ofthe polarizing plate 130, out of the linearly polarized light passingthrough the nanocapsule liquid crystal layer 200 passes through thepolarizing plate 130. Thus, a white is displayed.

In this case, it is preferred that a difference between the refractiveindex of the nanocapsule 220 and the refractive index of the liquidcrystal molecule 220 is within about ±0.1. The average refractive index(n) of the liquid crystal molecule 220 may be defined as follows:n=[(ne+2*no)/3] (where ne is a refractive index of a major axis of theliquid crystal molecule 220, and no is a refractive index of a minoraxis of the liquid crystal molecule 220).

Accordingly, the LCD including the nanocapsule liquid crystal layer 200can be used as a display device, with its transmittance changingaccording to a variation of the voltage applied.

Further, since the nanocapsule liquid crystal layer 200 does not have aninitial alignment to be optically anisotropic, alignment of liquidcrystal molecules may not be required, and thus no alignment layer maybe needed in the LCD 100, and also, processes for forming an alignmentlayer such as rubbing may not be needed.

Further, in case that the nanocapsules 230 are dispersed in the bufferlayer 210 made of, for example, liquid crystal, the nanocapsule liquidcrystal layer 200 may be formed, for example, by a printing method,coating method, or dispensing method. In case that the nanocapsules 230are dispersed in the buffer layer 210 made in a film type, thenanocapsule liquid crystal layer 200 may be formed, for example, by alamination method. Accordingly, a process of forming a gap between thefirst and second substrates filled with the liquid crystal layer in theprior art can be eliminated, and a process of forming the seal patternin the prior art can be eliminated.

Therefore, production efficiency can be improved.

Further, even when an external force such as a user's touch is appliedto the LCD of the embodiment, the liquid crystal molecules 220 are inthe nanocapsule 230 having a size less than the wavelength of visiblelight, thus there is substantially no influence of visible light, andthus light leakage due to the external force can be reduced orprevented.

Accordingly, in case that the LCD of the embodiment is applied as aflexible display device, even when the external force is applied to theLCD, because of the nanocapsule 230 having a size less than thewavelength of visible light, light leakage due to the external force canbe reduced or prevented.

Particularly, since the flexible type LCD of the embodiment includes thereflective polarizing film 127 on the front of the LED assembly 129, thelinearly polarized light from the backlight unit 160 is supplied to theliquid crystal panel 110. Accordingly, one polarizing plate can beeliminated.

Thus, the LCD of the embodiment may not require the second substrate (4of FIG. 2) and one polarizing plate (20 of FIG. 2) in the prior art,thus a total thickness of the liquid crystal panel 110 can be reduced,and thus the LCD can have lightweight and thin profile and can beeffectively applied as a flexible type display device.

Alternatively, since the nanocapsule liquid crystal layer 200 is formedwith the nanocapsules 230 dispersed in the buffer layer of liquidcrystal or in a film type, another flexible type LCD of an eighthembodiment may be provided as illustrated in FIG. 17C, in which thenanocapsule liquid crystal layer 200 is located facing the backlightunit 160, and in this case, the polarizing plate 130 is located on thetop surface of the substrate 112.

Alternatively, another flexible type LCD of the ninth embodiment may beprovided as illustrated in FIG. 17D, in which the nanocapsule liquidcrystal layer 200 is located facing the backlight unit 160 similarly tothe above eighth embodiment. Further, a touch panel 150 is located onthe liquid crystal panel 110 with the polarizing plate 130, and includesfirst electrode 151, an insulating layer 155, and a second electrode153. Thus, the flexible type LCD of this embodiment can be applied to atouch type display device.

In the above seventh to ninth embodiments, in addition to the reflectivepolarizing film 127, a wire-grid lattice may be formed in the lightguide plate 123 so that only a specific linearly polarized light passesthrough the light guide plate 123 and then is supplied to the liquidcrystal panel 110. Alternatively, in addition to the reflectivepolarizing film 127, a polarization separation layer may be formed onthe light guide plate 123 so that only a specific linearly polarizedlight passes through the light guide plate 123 and then is supplied tothe liquid crystal panel 110.

Tenth Embodiment

FIG. 18 is a schematic view illustrating a flexible type LCD accordingto the tenth embodiment of the present invention. Explanations of partssimilar to parts of the first to ninth embodiments may be omitted.

Referring to FIG. 18, the flexible type LCD includes a liquid crystalpanel 110 and a backlight unit 160. The liquid crystal panel 110includes a nanocapsule liquid crystal layer 200 on a substrate 112, onwhich the thin film transistor and the color filter 134 are formed.

Further, the pixel electrode 124 and the common electrode 136 are formedon the substrate 112.

The nanocapsule liquid crystal layer 200 includes the nanocapsules 230filled with the liquid crystal molecules 220 and dispersed in the bufferlayer 210.

The polarizing plate 130 is attached onto the polarizing plate 130, andthe backlight unit 160 is below the liquid crystal panel 110.

The backlight unit 160 includes non-polar or semi-polar LEDs 300arranged along a length direction of a side of the backlight unit 160,the reflection plate 125, the light guide plate 123 on the reflectionplate 125, and at least one optical sheet 121.

The non-polar or semi-polar LEDs 300 as light sources are located at andfaces the surface of the light guide plate 123 upon which the light isincident.

The non-polar or semi-polar LED 300 has a property of emitting lightpolarized in a specific direction.

The non-polar or semi-polar LED 300 is different from a polar LEDincluding a compound semiconductor layer grown in a c-axis direction.For example, by growing a nitride semiconductor layer of a GaN groupmaterial, such as GaN, InGaN, AlGaN, AlInGaN or the like, on a m-surfaceor a-surface of a GaN substrate, a non-polar or semi-polar LED withoutspontaneous polarization or piezoelectric polarization may be formed.

Further, an LED using a nitride semiconductor layer may be formed toemit light of wavelength in a range of UV light to visible light byadjusting a composition ratio of the nitride semiconductor.

A specific linearly polarized light entering the light guide plate 123from the non-polar or semi-polar LED 300 travels in the light guideplate 123 and evenly spreads over a large area of the light guide plate123, and thus a plane light is supplied to the liquid crystal panel 110.

The light guide plate 123 may include a specific-shaped pattern at abottom surface to supply a uniform plane light.

The reflection plate 125 is located below the light guide plate 123, andreflects light coming out from the bottom surface of the light guideplate 123 to the liquid crystal panel 110, and thus brightness of lightis improved.

The at least one optical sheet 121 may include a diffusion sheet, and atleast one light concentration sheet. The at least one optical sheet 121diffuses and/or concentrates light to supply more uniform plane light tothe liquid crystal panel 110.

When no voltage is applied to the liquid crystal panel 110, the liquidcrystal molecules 220 are arranged randomly, the liquid crystalmolecules 220 and the nano capsule 230 have different anisotropies inrefractive index from each other. Accordingly, optically isotropicproperty is obtained.

Accordingly, a linearly polarized light emitted from the backlight unit160 passes through the nanocapsule liquid crystal layer 200 as is, andthen does not pass through the polarizing plate 130 perpendicular to thepolarizing axis of the linearly polarized light from the backlight unit160. Thus, a black is displayed.

When a voltage is applied between the pixel electrode 124 and the commonelectrode 136, the liquid crystal molecules 220 are arranged parallelwith the electric field between the pixel and common electrodes 124 and136. Accordingly, a linearly polarized light, parallel with the liquidcrystal molecules 220, out of the linearly polarized light emitted fromthe backlight unit 160 passes through the nanocapsule liquid crystallayer 200.

Then, a linearly polarized light, parallel with the polarizing axis ofthe polarizing plate 130, out of the linearly polarized light passingthrough the nanocapsule liquid crystal layer 200 passes through thepolarizing plate 130. Thus, a white is displayed.

Eleventh Embodiment

FIG. 19A is a schematic view illustrating a flexible type LCD accordingto an eleventh embodiment of the present invention, and FIG. 19B is aschematic perspective view illustrating an optical fiber of an opticalfiber type light guide plate of FIG. 19A. Explanations of parts similarto parts of the first to tenth embodiments may be omitted.

Referring to FIGS. 19A and 19B, the flexible type LCD includes a liquidcrystal panel 110 and a backlight unit 160. The liquid crystal panel 110includes a nanocapsule liquid crystal layer 200 on a substrate 112, onwhich the thin film transistor and the color filter 134 are formed.

Further, the pixel electrode 124 and the common electrode 136 are formedon the substrate 112.

The nanocapsule liquid crystal layer 200 includes the nanocapsules 230filled with the liquid crystal molecules 220 and dispersed in the bufferlayer 210.

The polarizing plate 130 is attached onto the polarizing plate 130, andthe backlight unit 160 is below the liquid crystal panel 110.

The backlight unit 160 includes non-polar or semi-polar LEDs 300arranged along a length direction of a side of the backlight unit 160,the reflection plate 125, a light guide plate 400 on the reflectionplate 125, and at least one optical sheet 121. The light guide plate 123is an optical fiber type light guide plate.

The reflection plate 125 is located below the light guide plate 400, andreflects light coming out from the bottom surface of the light guideplate 400 to the liquid crystal panel 110, and thus brightness of lightis improved.

The at least one optical sheet 121 may include a diffusion sheet, and atleast one light concentration sheet. The at least one optical sheet 121diffuses and/or concentrates light from the light guide plate 400 tosupply more uniform plane light to the liquid crystal panel 110.

The non-polar or semi-polar LEDs 300 as light sources are located at andfaces the light incidence surface of the light guide plate 400.

The non-polar or semi-polar LED 300 has a property of emitting lightpolarized in a specific direction.

A specific linearly polarized light entering the light guide plate 400from the non-polar or semi-polar LED 300 travels in the light guideplate 400 and evenly spreads over a large area of the light guide plate400, and thus a plane light is supplied to the liquid crystal panel 110.

The light guide plate 400 is formed using a plurality of optical fibers410 which are arranged in parallel with each other to form a plate.

As illustrated in FIG. 19B, the optical fiber 410 includes a core 411 ata center portion, and a clad 413 enclosing an outer surface of the core411.

The clad 413 includes a light guide portion 413 a, which has arefractive index (n2) less than a refractive index (n1) of the core 411and in which a total internal reflection happens, and a light emissionportion 413 b which has a refractive index (n3) equal to or greater thanthe refractive index (n1) of the core 411 and which emits an internallight to the outside.

The refractive index (n1) of the core 411, the refractive index (n2) ofthe light guide portion 413 a, and the refractive index of the lightemission portion 413 b each have a range of about 1.2 to about 1.6greater than a refractive index of an air.

In other words, in order that a linearly polarized light from the LED300 traveling in the core 411 with a total reflection is emitted to theoutside at a certain position, the clad 413 has a refractive index at apredetermined position different from that at other position. That is,the light emission portion 413 b is formed to have a refractive indexdifferent from other portion.

When a refractive index of the clad 413 is less than that of the core411, an internal light of the core 411 travels being reflected insidethe core 411. However, when a refractive index of the clad 413 at acertain position is greater than that of the core 411, a condition forthe total internal reflection at the position is not met, a part of thelight traveling in the core 411 externally escapes from the opticalfiber 410.

In this regard, the light guide portion 413 a and the light emissionportion 413 b are configured to contact each other from an inner side ofthe clad 413 to an outer side of the clad 413.

The optical fibers 410 as above are bound to each other to form theoptical fiber type light guide plate 400. Accordingly, a backlight unit160 can be configured to emit light at a predetermined position on alength direction of the optical fiber 410.

In this embodiment, since the nanocapsule liquid crystal layer 200 doesnot have an initial alignment to be optically anisotropic, alignment ofliquid crystal molecules may not be required, and thus no alignmentlayer may be needed in the LCD 100, and also, processes for forming analignment layer such as rubbing may not be needed.

Further, in case that the nanocapsules 230 are dispersed in the bufferlayer 210 made of, for example, liquid crystal, the nanocapsule liquidcrystal layer 200 may be formed, for example, by a printing method,coating method, or dispensing method. In case that the nanocapsules 230are dispersed in the buffer layer 210 made in a film type, thenanocapsule liquid crystal layer 200 may be formed, for example, by alamination method. Accordingly, a process of forming a gap between thefirst and second substrates filled with the liquid crystal layer in theprior art can be eliminated, and a process of forming the seal patternin the prior art can be eliminated.

Therefore, production efficiency can be improved.

Further, even when an external force such as a user's touch is appliedto the LCD of the embodiment, the liquid crystal molecules 220 are inthe nanocapsule 230 having a size less than the wavelength of visiblelight, thus there is no influence of visible light, and thus lightleakage due to the external force can be reduced or prevented.

Accordingly, in case that the LCD of the embodiment is applied as aflexible display device, even when the external force is applied to theLCD, because of the nanocapsule 230 having a size less than thewavelength of visible light, light leakage due to the external force canbe prevented.

Particularly, since the flexible type LCD of the embodiment includes thenon-polar or semi-polar LED 300 emitting a predetermined linearlypolarized light, the linearly polarized light from the backlight unit160 is supplied to the liquid crystal panel 110. Accordingly, onepolarizing plate can be eliminated.

Thus, the LCD of the embodiment may not require the second substrate (4of FIG. 2) and one polarizing plate (20 of FIG. 2) in the prior art,thus a total thickness of the liquid crystal panel 110 can be reduced,and thus the LCD can have lightweight and thin profile and can beeffectively applied as the flexible type display device. Further, sincethe optical fiber type light guide plate 400 is used for the LCD, thebacklight unit 160 of thin-profile and high efficiency can be provided,and thus the flexible LCD can be applied to a bendable or rollabledisplay device.

Alternatively, the light guide plate (123 of one of FIGS. 17B to 17D) ofone of the seventh to ninth embodiments may be an optical fiber typelight guide plate. Further, in the LCD of the tenth or eleventhembodiment, the nanocapsule liquid crystal layer 200 may be located toface the backlight unit 160 like FIG. 17C or FIG. 17D.

Further, the LCD of the tenth or eleventh embodiment may employ theliquid crystal panel 110 and the backlight unit 160 modulized using alamination process. In this process, an adhesive is interposed betweenthe liquid crystal panel 110 and the backlight unit 120 to eliminate anair gap therebetween, and thus loss of light due to the air gap can beprevented.

It will be apparent to those skilled in the art that variousmodifications and variation can be made in the present invention withoutdeparting from the spirit or scope of the invention. Thus, it isintended that the present invention cover the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

What is claimed is:
 1. A reflective type liquid crystal display device comprising: a liquid crystal panel that includes a first electrode, a nanocapsule liquid crystal layer on the first electrode, and a second electrode on the nanocapsule liquid crystal layer, wherein the nanocapsule liquid crystal layer includes nano-sized capsules which are each filled with negative type liquid crystal molecules and are dispersed in a buffer layer; a polarizing plate that is on a surface of the liquid crystal layer through which an external light enters; a phase retardation plate between the polarizing plate and the liquid crystal panel; and a reflection plate that reflects light passing through the nanocapsule liquid crystal layer, wherein the nanocapsule liquid crystal layer has an optical anisotropy according to a voltage difference between voltages applied to the first and second electrodes, and has an optical isotropy when no voltages are applied to the first and second electrodes, and wherein the first electrode includes a vertex, a first inclined plane and a second inclined plane, such that the vertex is formed between the first inclined plane and the second inclined plane, wherein the second electrode includes a vertex, a first inclined plane and a second inclined plane, such that the vertex is formed between the first inclined plane and the second inclined plane, and wherein the first and second inclined planes of the first electrode are substantially parallel with the first and second inclined planes, respectively, of the second electrode.
 2. The device of claim 1, wherein the phase retardation plate is a λ/4 wave plate that have a following relation of refractive indices: nx=ny>nz.
 3. The device of claim 1, wherein a diameter of the nano-sized capsule is about 1 nm to about 320 nm.
 4. The device of claim 1, wherein a volume of the nano-sized capsule is about 25% to about 65% of a volume of the nanocapsule liquid crystal layer.
 5. The device of claim 1, wherein a thickness of the nanocapsule liquid crystal layer is about 2 um to about Sum.
 6. The device of claim 1, wherein a refractive index different between the liquid crystal molecule and the nano-sized capsule is about ±0.1.
 7. The device of claim 1, wherein the liquid crystal panel includes a first substrate on which the first electrode is formed, and wherein a thin film transistor is formed on the first substrate.
 8. The device of claim 7, wherein the second electrode is formed on the phase retardation plate or the polarizing plate.
 9. The device of claim 7, wherein the liquid crystal panel includes a second substrate facing the first substrate with the nanocapsule liquid crystal layer therebetween, and wherein the second electrode is formed on the second substrate.
 10. The device of claim 9, wherein a color filter is formed on the first substrate or second substrate.
 11. The device of claim 7, wherein the reflection plate is formed as a reflection electrode on the first substrate. 